The International Agency for Research on Cancer says glyphosate is "probably carcinogenic," which has led California to require warning labels on glyphosate products, the Associated Press reported.
However, California hasn't enforced the warning label rule because Roundup maker Monsanto last year obtained a court order blocking the warning labels until the lawsuit is resolved.
The EPA says its research shows the chemical poses no risks to public health and won't approve warning labels for glyphosate products, the AP reported.
The EPA considers labels warning glyphosate to cause cancer to "constitute a false and misleading statement," which is prohibited by federal law, Michael Goodis, director of the agency's registration division in its Office of Pesticide Programs, said in letters to companies explaining the EPA's stance.
Chandra Lord, a representative for Monsanto’s parent company Bayer AG, said the EPA’s announcement “is fully consistent with the science-based conclusions reached by the agency and leading health regulators worldwide for more than four decades.”
“Glyphosate is not carcinogenic,” Lord said.
It's unusual for the EPA to tell a state it can't go beyond the federal requirements, according to Brett Hartl, government affairs director for the Center for Biological Diversity.
"It's a little bit sad the EPA is the biggest cheerleader and defender of glyphosate," Hartl told the AP. "It's the Environmental Protection Agency, not the pesticide protection agency."
Glyphosate-related lawsuits involving about 13,000 plaintiffs are pending against Monsanto. Juries have awarded damages in each of three cases that went to trial in California.